The Sports Medicine Boot II (SMB II) is designed for use on the horse's front or hind legs. It is important to choose the correct size for your horse to get the optimum benefits from the SMBII. In the above chart are circumference and height measurements. The circumference measurement of the boot is more critical than the height because the boot must fit around the horse's leg and overlap 1/2" to 1.5" to be effective. When sizing, the height of the horse and the coarseness of the bone should also be taken into account, but these should not be the only determining factors.
As a general rule, horses will use one size larger on the hind legs than the front ones. For instance, many mature horses wear SMBII 100's (medium) on the front and SMB II 200's (Large) on the hind legs. However, instances where there is no pronounced size different in the fetlocks, the horse can wear the same size on the front and hind legs.
To choose the correct size, refer to the above chart. If you are still unsure which size to get, you should measure the circumference of your horse's front and rear fetlocks at the widest point. After doing so, choose the boot size that is the next bigger size than your measurement.
As an example, if your horse's fetlock measures 10.75" in the front and 11.5" in the rear, you should choose a pair of SMB II 100's (medium) for both the front and rear.